You create a second supplier - let’s call him Supplier B
You have entered a Purchase Invoice to Supplier A (the original supplier) to whom you owe the payment.
Supplier B pays Supplier A on your behalf - you record this using a Journal Entry - for example if invoice was for 10,400 Euro
If there is a fee involved, then you should record that as a Purchase Invoice from Supplier B for the amount of the fee
Supplier B’s account now records the correct amount that you now owe